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Nuclear new build procurement considerations
It may seem counterintuitive, but the best time to enhance the ability to support operations and maintenance for a new plant is before construction starts. This is one of many lessons learned by the currently operating nuclear fleet. As construction and startup of many nuclear facilities was completed, it quickly became evident that the ability to efficiently support operations and maintenance was limited. Most of the information necessary to establish and manage procurement of spare and replacement items, maintenance, and configuration of the facilities was unavailable and had to be gathered on a case-by-case, “on-demand” basis. Absence of necessary information and the associated challenges resulted in the need for staff augmentation and multiyear-long projects to develop equipment bills of material and maintenance programs and to perform technical evaluations for the huge quantities of spare and replacement items being requested.
Chu-Tien Chen, Shih-Hai Li
Nuclear Technology | Volume 117 | Number 2 | February 1997 | Pages 223-233
Technical Paper | Radioactive Waste Management | doi.org/10.13182/NT97-A35327
Articles are hosted by Taylor and Francis Online.
An analytical solution is developed for the problem of radionuclide transport in a system of planar parallel fractures situated in a porous rock matrix. The flux at the inlet boundary of a fracture is assumed to decrease exponentially with time. The solution considers the following processes: (a) advective transport in the fractures, (b) mechanical dispersion and molecular diffusion along the fractures, (c) molecular diffusion from a fracture to the porous matrix, (d) adsorption onto the fracture wall, (e) adsorption within the porous matrix, and (f) radioactive decay. The solution is based on the Laplace transform method. The general transient solution is in the form of a double integral that is evaluated using composite Gauss-Legendre quadrature. A simpler transient solution that is in the form of a single integral is also presented for the case that assumes negligible longitudinal dispersion along the fractures. A few examples are given to illustrate the effect of various fracture spacings and groundwater velocities, a 1% penetration distance, and the effect of neglecting the longitudinal dispersion in the fractures.